#define _CRT_SECURE_NO_WARNINGS 1

#include<iostream>
#include<vector>

using namespace std;

string smallestString(string s) {
    char prev = -1;
    bool flag = false;
    for (int i = 0; i < s.size(); i++)
    {
        if (s[i] != 'a')
        {
            flag = true;
            s[i] -= 1;
            prev = s[i];
        }
        else
        {
            if (prev != -1)
                break;
        }
    }
    if (flag == false)
        s[s.size() - 1] = 'z';
    return s;
}

int main()
{
    string s = "a";
    smallestString(s);
    return 0;
}